Device and method of verifying protective case usage

ABSTRACT

A device and method of verifying protective case usage, is described. The device includes one or more processors to drive an electromechanical transducer with an input signal. The electromechanical transducer generates an input force based on the input signal, and a sensor of the device generates a test output signal in response to the input force. The one or more processors determine, based on the test output signal, a level of verification that a protective case is mounted on the device. The determination can include determining whether the test output signal matches a predetermined impulse response signal indicative of an unprotected device or a protected device. A digital identification tag of the protective case can be read by a radio-frequency transceiver of the device to provide an additional level of verification that the protective case is mounted on the device. Other aspects are described and claimed.

This application claims the benefit of priority of U.S. ProvisionalPatent Application No. 62/609,255, filed on Dec. 21, 2017, and U.S.Provisional Patent Application No. 62/738,488, filed on Sep. 28, 2018,and incorporates herein by reference those provisional patentapplications.

BACKGROUND Field

Aspects related to portable electronic devices are disclosed. Moreparticularly, aspects related to portable electronic devices configuredfor use with protective cases are disclosed.

Background Information

Mobile devices, such as smartphones, are ubiquitous. Despite theirprevalence, however, mobile devices have steadily increased in costsince their inception more than a decade ago. Some smartphones todayretail new for over a thousand dollars, and smartphone repair orreplacement can cost several hundred dollars.

The high initial and ongoing costs of mobile devices has led many mobiledevice owners to protect their devices with a protective case.Typically, the cost of a protective case is justified by the concern ofpossibly damaging the mobile device in the event it is dropped orexposed to a liquid. More particularly, the protective case mitigatesthe risk of loss resulting from costly repair or replacement of mobiledevices that have been damaged by impact or submersion. Statistics showthat the concern of damage is warranted: Americans have spent about fourbillion dollars on smartphone repairs in a single year.

SUMMARY

A mobile device that has been protected against impact or submersion maybe more valuable than a counterpart device that has been unprotectedagainst such events. For example, an owner of a smartphone may be ableto sell the device at a higher price if the prospective buyer believesthat the device was well-cared for and protected. There has not been away, however, for the buyer to objectively verify that the ownerprotected the device during prior use. Similarly, companies that issuecompany-owned tablet computers to employees can protect their investmentby requiring the computers to remain within a protective case duringuse. The company, however, has not been able to objectively verify thatthe employee followed company policy by keeping the computer in aprotective case. Without the ability to objectively verify protectivecase usage on a device, it may not be possible to differentiate thevalue of devices having different protection histories, or implementprotection policies that will protect the investment of all parties toan equipment use agreement.

A device and a method of verifying protective case usage on the device,is described. The device can determine one or more levels ofverification to verify that a protective case is mounted on the device.Furthermore, the device can determine an amount of time that theprotective case is mounted on the device, e.g., a percentage of timethat the device has been protected since purchase. The device can reportthe protective case verification data to a remote server, which cantrack the protection history of the device. The protection history canbe valuable information, for example, when an owner of the devicedecides to sell the device. More particularly, the protection historycan be reviewed by a prospective buyer to verify that the device hasbeen protected by the seller, and thus, should be in good condition.Accordingly, the prospective buyer may be more likely to buy the deviceand/or more likely to buy the device at a higher price. In summary, adevice that is configured to verify and track protective case usage canincrease the value of the device in the marketplace.

The device can perform a protected case verification (PCV) test toverify protective case usage. The device can include driving anelectromechanical transducer, e.g., a vibration motor, inside of thedevice with an input signal to cause the electromechanical transducer togenerate an input force. A sensor, e.g., an accelerometer, inside of thedevice can detect the input force, and in response, generate a testoutput signal. One or more processors of the device can receive the testoutput signal and determine whether a protective case is mounted on thedevice based on the test output signal. For example, frequency contentof the test output signal can define an impulse response of the deviceresponsive to the input force. The test impulse response can be comparedto a known impulse response for a standalone device to determine whetherthe test data matches the reference data. Mismatched data can provide afirst level of verification that the device is protected. Similarly, thetest impulse response can be compared to a known impulse response for adevice-case system to determine whether the test data matches thereference data. Matching data can provide a second level of verificationthat the device is protected. In an aspect, the protective case caninclude a communication device, e.g., a digital identification (ID) tagsuch as a near-field communication (NFC) tag, storing an identifier. Theidentifier can be unique to the protective case and/or specific to abrand/model of the case. The device can read the digital ID tag todetermine whether the identifier matches a reference case identifier.Matching identifiers can provide a third level of verification that thedevice is protected.

The device can communicate verification information to a remote serverfor inclusion in a PCV test report. For example, the PCV test report canindicate a highest level of verification achieved, e.g., the firstlevel, the second level, or the third level, and/or a percentage of timethat the device was protected. The PCV test report can be relied on byinterested parties, e.g., a prospective buyer of the device or a companythat has issued the device to an employee, to verify that the device hasbeen used as expected.

The above summary does not include an exhaustive list of all aspects ofthe present invention. It is contemplated that the invention includesall systems and methods that can be practiced from all suitablecombinations of the various aspects summarized above, as well as thosedisclosed in the Detailed Description below and particularly pointed outin the claims filed with the application. Such combinations haveparticular advantages not specifically recited in the above summary.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorial view of a device-case system, in accordance withan aspect.

FIG. 2 is a pictorial view of a protective case, in accordance with anaspect.

FIG. 3 is a block diagram of a system for verifying protective caseusage, in accordance with an aspect.

FIG. 4 is a schematic view of a device-case system configured to verifyprotective case usage, in accordance with an aspect.

FIG. 5 is a flowchart of a method of monitoring protective case usage ofa device, in accordance with an aspect.

FIG. 6 is a flowchart of a method of verifying protective case usage, inaccordance with an aspect.

FIG. 7 is a graphical view of a test output signal and a baseline outputsignal, in accordance with an aspect.

FIG. 8 is a graphical view of a comparison between a test impulseresponse and a baseline impulse response indicative of an unprotecteddevice, in accordance with an aspect.

FIG. 9 is a graphical view of a comparison between a test impulseresponse and a baseline impulse response indicative of a protecteddevice, in accordance with an aspect.

FIG. 10 is a pictorial view of a protective case verification reportdocumenting protective case usage by a device, in accordance with anaspect.

FIG. 11 is a block diagram of a system having a dormant near-fieldcommunication tag for verifying protective case usage, in accordancewith an aspect.

FIG. 12 is a block diagram of a system having a dormant Bluetoothcommunication tag for verifying protective case usage, in accordancewith an aspect.

DETAILED DESCRIPTION

Aspects describe a device and a method of verifying protective caseusage. The device can be a mobile device, such as a smartphone, and candetermine that a protective case is mounted on the device based on animpulse response of the smartphone to a driving force. The device,however, can be another mobile device, such as a tablet computer, alaptop computer, or headphones, to name only a few possibleapplications.

In various aspects, description is made with reference to the figures.However, certain aspects may be practiced without one or more of thesespecific details, or in combination with other known methods andconfigurations. In the following description, numerous specific detailsare set forth, such as specific configurations, dimensions, andprocesses, in order to provide a thorough understanding of the aspects.In other instances, well-known processes and manufacturing techniqueshave not been described in particular detail in order to notunnecessarily obscure the description. Reference throughout thisspecification to “one aspect,” “an aspect,” or the like, means that aparticular feature, structure, configuration, or characteristicdescribed is included in at least one aspect. Thus, the appearance ofthe phrase “one aspect,” “an aspect,” or the like, in various placesthroughout this specification are not necessarily referring to the sameaspect. Furthermore, the particular features, structures,configurations, or characteristics may be combined in any suitablemanner in one or more aspects.

The use of relative terms throughout the description may denote arelative position or direction. For example, “above” may indicate afirst direction away from a reference point. Similarly, “below” mayindicate a location in a second direction away from the reference pointand opposite to the first direction. Such terms are provided toestablish relative frames of reference, however, and are not intended tolimit the use or orientation of a device or a protective case to aspecific configuration described in the various aspects below.

In an aspect, a device, such as a smartphone, performs a self-test todetermine whether a protective case is installed on the device at thetime that the test is performed. The device includes one or moreprocessors that can drive an electromechanical transducer of the deviceto generate an input force. For example, electromechanical transducercan be driven by an input signal to generate a test vibration signal.One or more sensors of the device, e.g., a three-axis accelerometer, candetect the input force and generate a corresponding output signal. Theone or more processors can determine, based on the output signal,whether the protective case is mounted on the device. For example, theone or more processors can perform a fast Fourier transform (FFT)algorithm on the output signal to determine a spectral frequency contentof the output signal, and compare the spectral frequency content to apredetermined impulse response signal that is indicative of anunprotected device or a protected device. Based on the comparison, theone or more processors can determine whether the device is protected orunprotected. The test results can be reported to and stored by a remoteserver for future use. For example, the remote server can sendnotifications to parties interested in knowing whether the device isusing, or has used, a protective case.

Referring to FIG. 1, a pictorial view of a device-case system is shownin accordance with an aspect. A device-case system 100 can be acombination of a device and a protective case. For example, device-casesystem 100 can be a reference protective case 102 mounted on a referencedevice 104. Reference device can be a smartphone, a tablet computer, oranother mobile device. Reference device can be any of numerousbrands/models of mobile devices having touchscreens and processorscapable of downloading and running mobile software applications.Reference case 102 can be any of numerous brands/models of protectivecase accessory products that help prevent damage to a mobile device inthe event the mobile device is exposed to mechanical shock and/or liquidcontact.

Reference device 104 and reference case 102 may have known mechanicalcharacteristics that affect an impulse response of device-case system100 to an input force. For example, reference case 102 may be formedfrom particular materials, e.g., plastic or rubber compounds, with aparticular size, e.g., shape, thickness, or weight, to protect referencedevice 104. More particularly, reference case 102 absorbs energy and/orresonates energy in a particular manner when subjected to a vibrationalstimulus, and thus, device-case system 100 has a particular impulseresponse to an input force when reference device 104 is installed inreference case 102.

Referring to FIG. 2, a pictorial view of a protective case is shown inaccordance with an aspect. As described above, a protective case 200 canhave particular geometrical features conducive to protecting a mobiledevice when mounted on the mobile device. For example, protective case200 can include one or more walls 202 or corners formed from respectivematerials and thickness to absorb mechanical shock when device-casesystem 100 is dropped by a user. Protective case 200 can have one ormore holes 204 to allow for light or sound to pass between the mobiledevice and a surrounding environment. Protective case 200 can includeother features, such as a front cover (not shown) to provide addedprotection to a display of the mobile device, e.g., by preventing liquidfrom directly contacting the display when protective case 200 is exposedto water.

In an aspect, protective case 200 includes a digital identification (ID)tag 206. For example, digital ID tag 206 can be attached to an interiorof protective case 200. The interior can surround a cavity that receivesthe mobile device. Digital ID tag 206 can be permanently orsemi-permanently affixed to wall 202. Digital ID tag 206 can be aself-adhesive tag. Digital ID tag 206 can be attached to wall 202 usingbonding techniques, such as gluing or welding. In an aspect, digital IDtag 206 can be embedded in wall 202 of protective case 200. For example,digital ID tag 206 may be molded, e.g., insert molded, into wall 202during the manufacture of protective case 200.

Digital ID tag 206 can store information corresponding to protectivecase 200. For example, digital ID tag 206 can store an identifier ofprotective case 200. In an aspect, digital ID tag 206 is a passive tag,e.g., a passive near-field communication (NFC) tag, capable of beingprogrammed with the identifier. The identifier can be an encrypteddigital identification code that is assigned to a specific brand ormodel of protective case 200. Digital ID tag 206 can be programmed withthe identifier during manufacture of the particular case, and can beaffixed inside the particular case during the manufacture. Digital IDtag 206 may be affixed inside protective case 200 at a location suchthat a radio frequency (RF) transceiver, e.g., an NFC reader, of themobile device can read digital ID tag 206 after the mobile device isinstalled in protective case 200. Alternatively, digital ID tag 206 maybe affixed inside protective case 200 at a location where it is notreadable by the RF transceiver after installation. In the latter case,the RF transceiver can read the identifier from the digital ID tag 206during a setup procedure before the mobile device is installed in theprotective case 200.

It will be appreciated that, although the digital ID tag 206 ofprotective case 200 is referred to as being “NFC” tag 206 throughoutthis description, protective case 200 can include an alternativecommunication tag. For example, digital ID tag 206 can be a passiveradio-frequency identification (RFID) tag operating within a differentradio frequency band to store and communicate the identifier to themobile device. It is noteworthy that NFC operates in a range that isless than a range of RFID. For example, NFC typically works in a rangeof less than twenty centimeters, whereas RFID typically works in a rangeof one meter or more. If the mobile device does not support NFC or RFIDradio frequency communications, the identifier can be embedded into aBluetooth (BT) tag. For example, digital ID tag 206 can include anactive or passive Bluetooth Low Energy (BTLE) beacon device, whichtypically works in a range of about thirty meters, or anothercommunication device using another communication protocol. In an aspect,digital ID tag 206 includes a dormant BT tag, as described further withrespect to FIG. 12 below. The short range of NFC can allow goodcommunication between an NFC reader contained within the mobile deviceand NFC tag 206 of protective case 200, which is in direct contact withthe mobile device. In an aspect, digital ID tag 206 includes a dormantNFC tag, as described further with respect to FIG. 11 below.Accordingly, it will be appreciated that one embodiment of digital IDtag 206 described below, e.g., an NFC tag, may be substituted foranother embodiment of digital ID tag 206, e.g., a BT tag, in the contextof the systems and methods described below.

Referring to FIG. 3, a block diagram of a system for verifyingprotective case usage is shown in accordance with an aspect. Aprotective case verification (PCV) system 300 can include a device 302,which can be any of several types of portable devices 302 or apparatuseswith circuitry suited to specific functionality. Similarly, PCV system300 can include a remote server 304, which can be any of several typesof computer systems with circuitry suited to specific functionality.Accordingly, the diagrammed circuitry is provided by way of example andnot limitation.

Device 302 may include one or more device processors 306 to executeinstructions to carry out the different functions and capabilitiesdescribed below. Instructions executed by device processor(s) 306 may beretrieved from a device memory 308, which may include a non-transitorymachine readable medium. The instructions may be in the form of anoperating system program having device drivers and/or one or moresoftware applications for performing operations according to the methodsdescribed below.

To perform the various functions, device processor(s) 306 may directlyor indirectly implement control loops and receive input signals from,and/or provide output signals to, other electronic components. Forexample, device processor(s) 306 may drive an electromechanicaltransducer 310 with an input signal to generate an input force.Electromechanical transducer 310 can be an actuator configured to covertthe input signal, e.g., an electrical voltage, into motion. For example,electromechanical transducer 310 can be configured to generate avibration, which applies an input force to device 302. In an aspect,electromechanical transducer 310 is a vibration motor configured togenerate a predetermined vibration signal based on variations in theelectrical input signal. The vibration motor can have an off-balanceweight attached to an end of an electric motor shaft such thatactivation of the electric motor causes the offset weight to spin andproduce mechanical vibration. The mechanical vibration can apply theinput force to other components of device 302, such as sensors 312,indirectly via transmission through a housing of device 302, ordirectly.

Electromechanical transducer 310 may include other types of actuatorsconfigured to generate the input force. In an aspect, electromechanicaltransducer 310 is a haptic vibration engine. The haptic electroniccomponent can be used to create the mechanical vibration. This type ofactuator, which is capable of creating the mechanical vibration insidedevice 302, can be characterized as a type of linear oscillator. Thehaptic vibration engine receives the input signal from deviceprocessor(s) 306. The input signal determines a waveform shape of themechanical vibration pattern and may include segments of differingfrequency, amplitude, and waveform shape.

Device 302 can include one or more sensors 312 configured to generate anoutput signal (FIG. 7) corresponding to inputs from other devicecomponents. For example, as described below, device 302 can include anelectromechanical sensor 312 configured to generate a baseline outputsignal in response to a baseline input signal, or a test output signalin response to a test input signal. The output signal(s) may begenerated in response to the input force(s) generated byelectromechanical transducer 310. In an aspect, the electromechanicalsensor 312 is an accelerometer configured to generate the output signalin response to the predetermined vibration signal. The accelerometer canbe a 3-axis micro-electronic accelerometer device fabricated using microelectro-mechanical systems (MEMS) technology. The 3-axis accelerometercan generate the output signal having three components, e.g.,acceleration of device 302 and/or the sensor 312 along three principalaxes.

The one or more sensors 312 of device 302 can include other types ofsensors for detecting movement of device 302 and/or the sensor 312 inresponse to external forces. For example, the one or more sensors 312can include a gyroscope to measure an angular rate of change of device302 by monitoring the Coriolis Effect. The gyroscope can be a 3-axisgyroscope fabricated using MEMS technology. Similarly, device 302 caninclude a compass (a digital magnetometer) capable of sensing the HallEffect to measure a magnetic field of the earth. The compass can providean output signal corresponding to a direction and/or bearing of device302.

The motion sensors 312 described above can be configured to generate amotion signal corresponding to movement of device 302. Furthermore,device processor(s) 306 can include a motion co-processor designedspecifically to monitor, collect, and interpret the motion data from theone or more sensors 312. The motion data can be interpreted andsummarized by the motion co-processor, stored in device memory 308 foruse in the operations described below, and/or communicated to remoteserver 304.

In an aspect, device processor(s) 306 can access and retrieve datastored in device memory 308 for various uses. For example, the outputsignal data from the one or more sensors 312 indicating device and/orsensor movement can be used by one or more application running on device302. The applications can control phone, music playback, or web browsingfunctions, by way of example. In an aspect, the applications include aPCV test application 314 that controls a protective case usageverification function. The application programs can run on top of theoperating system.

Optionally, device 302 can include an RF transceiver 350. For example,RF transceiver 350 can include an NFC reader 350 (FIG. 11) or aBluetooth (BT) radio (FIG. 12). NFC reader 350 can include a transceivercontroller and a transceiver antenna to effectuate communicationsbetween device 302 and protective case 200. For example, transceiverreader 350 can be configured to query digital ID tag 206 for informationabout protective case 200. In an aspect, RF transceiver 350 isconfigured to read the identifier of protective case 200 from digital IDtag 206. As described above, NFC tag 206 can be mounted on protectivecase 200, and can be read by NFC reader 350 before or after installingdevice 302 in protective case 200.

Device processor(s) 306 can receive input signals from, and outputsignals to, other device components. For example, device 302 can includemicrophone transducers to support cellular communication and audiorecording functionality. The microphone transducers can be used by phoneor PCV test applications on device 302 to record audio data files, whichcan then be processed by device processor(s) 306. As described below,the microphones can be used as sensors to sense input signals from oneor more speakers in an alternative PCV test configuration.

Device processor(s) 306 can receive input signals from menu buttons ofdevice 302, including through input selections of user interfaceelements displayed on a display. In an aspect, device processor(s) 306can provide output signals to the speaker(s) of device 302. For example,device 302 can include a left speaker and a right speaker, which may beindependently driven by an audio signal generated by device processor(s)306.

Device 302 and remote server 304 of PCV system 300 can includerespective communication circuitry 316 for establishing electroniccommunication. Communication circuitry 316 of device 302 can include oneor more of an NFC radio, a WiFi wireless LAN radio, a Bluetooth wirelessradio, a cellular wireless radio, or a GPS radio receiver. For example,device 302 can include RF circuitry 316 to transmit data, such asverification information 318 described below, to remote server 304.

Remote server 304, which may be networked directly with device 302through wireless communications via RF circuitry or indirectly through acomputer network, a telephone network, the Internet, etc., may includeone or more server processors 320 to execute instructions to carry outthe different functions and capabilities described below. Instructionsexecuted by server processor(s) 320 may be retrieved from a servermemory 322, which may include a non-transitory machine readable mediumof a data storage device. The instructions may be in the form of anoperating system program having device drivers and/or one or moresoftware applications 324 running on remote server 304 for performingoperations according to the methods described below. For example, serversoftware 324 can include database applications used for recordingverification information 318 provided by device 302. Server software 324can include PCV report generation software, which can create PCVreports, as described below.

Server processor(s) 320 can receive input signals from, and outputsignals to, other server components. For example, remote server 304 caninclude input devices, such as cursor control devices, e.g., a mouse,and alpha-numeric input devices, e.g., a keyboard, to allow a user tointeract with data and information displayed on a display device.

Communication circuitry 316 of remote server 304 can include one or moreof an NFC radio, a WiFi wireless LAN radio, a Bluetooth wireless radio,a cellular wireless radio, or a GPS radio receiver. Furthermore,communication circuitry 316 can include a network communicationinterface, such as a network interface controller, to connect remoteserver 304 to a computer network. Communication circuitry 316 of remoteserver 304 can be used to transmit data, such as PCV reports, to device302 or to other connected computing apparatuses within the network.

Referring to FIG. 4, a schematic view of a device-case system configuredto verify protective case usage is shown in accordance with an aspect.Several components of device-case system 100, which includes device 302installed in protective case 200, are described above. In an aspect, thedevice components can be contained within a device housing. Moreparticularly, device 302 may include an internal circuit board 402,which is fastened to the housing in a device interior. Several devicecomponents, such as device processor 306, device memory 308, sensor 312,electromechanical transducer 310, and RF transceiver 350, may be mountedon internal circuit board 402. Other circuitry, such as a motor drivecircuit 404, can be mounted on internal circuit board 402 and placed incommunication with device processor 306. Accordingly, device processor306 can drive electromechanical transducer 310, using motor drivecircuit 404, with an input signal to generate an input force 406 that ismechanically transmitted through internal circuit board 402 and/or thedevice housing. Input force 406 can be detected by sensor 312, andsensor 312 can generate a corresponding output signal (e.g., a baselineoutput signal or a test output signal as shown in FIG. 7), which iscommunicated to device processor 306 and/or device memory 308.

NFC tag 206 can be mounted on wall 202 of protective case 200 tocommunicate with NFC reader 350. As described above, NFC tag 206 mayalternatively be an RFID tag, a BTLE beacon, or another communicationdevice having a longer range than an NFC device, and being capable ofbeing programmed with an encrypted identifier that corresponds to aspecific brand/model of protective case 200. After programming thecommunication device, e.g., a BTLE beacon, with the identifier, thecommunication device can begin automatically periodically broadcastingthe encrypted identifier to the corresponding circuitry of device 302intended to read the identifier.

Device 302 can be powered by an internal battery 410 contained withinthe device housing. Battery 410 can be rechargeable. For example, device302 can include a near-field charging antenna 412 to enable device 302to support wireless charging of battery 410. Near-field charging antenna412 can be a loop antenna having a specialized geometry. The loopantenna can interface with a wireless charging plate 414 external to thedevice housing. The wireless charging plate 414 can be a mobile deviceaccessory that transmits radiofrequency energy capable of rechargingbattery 410 inside device 302. The radiofrequency energy can induceelectrical current within the loop antenna device to recharge battery410 of a smart phone, a watch, a tablet computer, etc.

Referring to FIG. 5, a flowchart of a method of monitoring protectivecase usage of a device is shown in accordance with an aspect. At aninitial stage 502, a user of device 302 can install and configure PCVtest application 314. PCV test application 314 can be installed on asmartphone to work with a vibration motor and accelerometer componentinside the smartphone to determine whether the smartphone is installedinside of protective case 200. More particularly, PCV test application314 can perform self-contained periodic testing, e.g., daily testing,using internal hardware components to verify and record a presence (orabsence) of an external protective case on device 302 at the time of thetest.

At stage 502, device processor(s) 306 set up PCV test application 314 ondevice 302. Device processor(s) 306 can execute application softwarethat leads the user through initialization tasks. The initializationtasks can include: creating a user login and account to associate device302 with the remote database on remote server 304, verify functionalityof sensors 312, recording a baseline frequency response indicative ofdevice 302 without protective case 200, or entering information aboutprotective case 200 to determine a frequency response spectrum specificto protective case 200 and/or device-case system 100 having a similarreference device 104 installed in a similar reference case 102.

In an aspect, PCV test application 314 can prompt the user of device 302to create an account on remote server 304. Creation of the account caninclude a user input of a user name and/or password. The user canassociate device 302 and protective case 200 with the account usingalphanumeric entries, selections of products from lists, etc. A make,model, or serial number of device 302 can be recorded for the account.Similarly, a make, model, or serial number of protective case 200 can berecorded for the account. In an aspect, the identification informationfor device 302 can be gathered automatically by server processor 320from device processor 306 without a need for user input. Similarly, theidentification information for protective case 200, e.g., the identifierof protective case 200, can be gathered automatically by deviceprocessor 306 from NFC tag 206 using NFC reader 350.

The configuration of PCV test application 314 can include determiningimpulse response signals indicative of device 302 not being protected byprotective case 200. In an aspect, device processor(s) 306 can execute a“stand alone” test sequence to determine the predetermined impulseresponse signal indicative of device 302 not protected by protectivecase 200. To collect baseline “stand-alone” accelerometer time domaindata, device processor(s) 306 can be configured to driveelectromechanical transducer 310 with a baseline input signal whenprotective case 200 is not mounted on device 302. Electromechanicaltransducer 310 can generate a baseline force, e.g., as part of avibration, and the baseline force can be transmitted through internalcircuit board 402 and/or the device housing, which is unprotected.Sensor 312, e.g., an accelerometer, of device 302 can detect thebaseline input force and generate a corresponding baseline outputsignal. The baseline output signal can be time domain data representingan impulse response of device 302 when electromechanical transducer 310is actuated without protective case 200 installed to absorb thevibration energy. Device processor(s) 306 can receive the baselineoutput signal generated by the one or more sensors 312 of device 302 inresponse to the baseline force. In an aspect, device processor(s) 306can determine the predetermined impulse response signal based on thebaseline output signal. For example, device processor(s) 306 can applyan FFT algorithm to the collected time domain data to generate afrequency response spectrum. FFT algorithm can be a fast computationalalgorithm for performing a discrete Fourier transform (DFT). The FFTalgorithm can be used to process the accelerometer waveform data (timedomain data) to create a corresponding frequency response spectrum(frequency domain data). The generated frequency response spectrum canrepresent the impulse response signal for the unprotected device 302,and thus, can be the predetermined impulse response signal. Thepredetermined impulse response signal can be used to verify whetherprotective case 200 is being used on device 302, as described below.

The configuration of PCV test application 314 can include determiningimpulse response signals indicative of device 302 being protected byprotective case 200. In an aspect, device processor(s) 306 can retrievea predetermined impulse response signal from one or more memorylocations of PCV system 300. For example, device processor(s) 306 canexecute searches on one or more library collections in an in-applicationlibrary collection, in a database stored in device memory 308 or servermemory 322, or in any other networked location. The search can be for aknown frequency response spectrum. The known frequency response spectrumcan represent an impulse response of reference case 102 that is similarto protective case 200, reference device 104 that is similar to device302, or a combination of reference device 104 and reference case 102that is similar to device-case system 100 having protective case 200mounted on device 302. Accordingly, the known frequency responsespectrum can represent the impulse response signal for device-casesystem 100, and thus, can be the predetermined impulse response signal.The predetermined impulse response signal can be used to verify whetherprotective case 200 is being used on device 302, as described below.

The referenced library collection(s) can be sets of known frequencyresponse spectrums associated with the most popular makes and models ofsmartphone protective cases being sold in the marketplace. The librarycollection(s) of frequency response spectrums is used by PCV testapplication 314 to acquire the branded case frequency response spectrummatching the brand/model of protective case 200 being installed ondevice 302 by the user.

During the installation and configuration of PCV test application 314,the user can install device 302 into protective case 200. When device302 is inserted into the interior of protective case 200, PCV testapplication 314 may attempt to automatically confirm that protectivecase 200 is the case product that the user designated. For example, NFCreader 350 of device 302 may attempt to read and/or record theidentifier from NFC tag 206. The identifier can be a digitalidentification code having a data string. The digital identificationcode can include coding that identifies the specific brand and model ofdevice(s) intended to fit into protective case 200. Also embedded in thedata string can be coding that identifies the brand and model number ofprotective case 200. The data string can also include coding segmentsfor the serial number and/or date of manufacture of the protective case200. Additionally, the data string can include coding to convey thematerial types and properties, such as density and durometer, of therubber or plastic materials used in the fabrication of the protectivecase 200. Furthermore, the digital identifier code can include codingsegments to convey additional mechanical properties of the protectivecase 200 such as weight, geometry (length, width, or thickness), andcase type/style. The digital identifier code may include a segment witha URL address that links directly to the known frequency responsespectrum of that particular brand/model of protective case 200 and/orthe known frequency response spectrum of that particular case used incombination with the particular device 302 associated with the PCVaccount.

The digital identification code stored in the identifier of NFC tag 206may be encrypted using asymmetric keys, e.g., a public key/private keycombination. It is noted that encrypting the digital identifier code canprevent manufacturers of black market counterfeit protective cases 200from being able to copy the digital identifier code. If manufacturerswere able to copy the digital identifier codes, some manufacturers couldattempt to trick the PCV test application 314 to allow counterfeitprotective cases 200 to masquerade as genuine protective cases 200.

At stage 504, device processor(s) 306 can execute a test timer sequenceof PCV test application 314. The test timer sequence monitors a time ofa system clock running on device 302 and initiates a test start commandwhen the timer function indicates that a predetermined state occurs. Forexample, PCV test application 314 can be configured to perform PCVtesting at pre-specified or random times. In an aspect, PCV testapplication 314 performs daily testing of device-case system 100. Forexample, a default start time, e.g., 3 a.m., can be set in PCV testapplication 314. Alternatively, the default start time can be a timereferenced to an event, such as at a random time occurring after atleast one hour of immobility (non-movement) of device 302. The testtimer function can monitor the system clock and/or system outputs suchas a motion signal from sensor(s) 312 to determine when the startcondition is met. For example, the test timer function can monitor thesystem clock to determine whether it is 3 a.m., or the test timerfunction can monitor data sampled by a gyroscope, an accelerometer,and/or a motion co-processor to determine whether device 302 iscurrently, or has recently, been in motion. When the monitored systemoutputs match or satisfy the predetermined condition(s), PCV testapplication 314 can initiate a PCV test.

When the predetermined condition(s) of the test timer function are notmet, e.g., when motion is detected by sensor(s) 312 or processor(s) 306of device 302, the PCV test can be rescheduled for a later time. Forexample, when device 302 is moving at a default start time, the starttime can be delayed by a predetermined amount of time, e.g., one hour.Similarly, when the test timer function determines that device 302 hasnot been stationary for the predetermined period of immobility, the testtimer function can continue to monitor device motion until the period ofimmobility is met.

At stage 506, device processor(s) 306 can execute a PCV test sequence ofPCV test application 314. The PCV test can determine whether protectivecase 200 is installed on device 302 by using the device components tocreate and monitor an impulse response of device 302 and then comparefrequency content of the impulse response to predetermined informationabout an impulse response of device-case system 100 or a referencedevice-case system. The operations of stage 506 relate to aspects shownin FIGS. 6-9, which are described in combination below.

Referring to FIG. 6, a flowchart of a method of verifying protectivecase usage is shown in accordance with an aspect. When the start commandinitiates the PCV test, PCV test application 314 may present anotification window on the display of device 302 to inform the user thatthe PCV test is about to be executed. As a preliminary operation in thePCV test, the PCV test application 314 may record a charging status ofbattery 410, and orientation data corresponding to a position ormovement of device 302. For example, PCV test application 314 can recorddata from the compass, the gyroscope, or the accelerometer asinformation indicative of a preliminary state of device 302 and/ordevice-case system 100.

At operation 602, when the PCV test application 314 receives the startcommand, device processor(s) 306 can drive electromechanical transducer310 with an input signal to generate input force 406. The input signalcan have a predetermined pattern to generate a predetermined vibrationsignal, e.g., a vibration test pattern. The vibration test pattern caninclude several waveform segments with respective waveform shapes,frequencies, or amplitudes. For example, the input signal can be asinusoidal signal provided to electromechanical transducer 310 over aperiod of time, e.g., 3 seconds, to cause a corresponding constantvibration of electromechanical transducer 310 over the 3 second period.

At operation 604, sensor(s) 312 of device 302 can generate an outputsignal in response to input force 406. Device processor(s) 306 canreceive the output signal from sensor(s) 312 over the period of timethat electromechanical transducer 310 generates the vibration testpattern. For example, device processor(s) 306 can read and record datafrom sensor(s) 312 for a 3 second period after device processor(s) 306begin driving electromechanical transducer 310. Similarly, deviceprocessor(s) 306 can simultaneously monitor the gyroscope and thecompass to collect the motion signal(s) for test signal validityconfirmation, as described below.

In an aspect, device processor(s) 306 can use the motion signal datareceived from one or more sensors 312 of device 302 to determine whetherthe output signal corresponding to the input force 406 is a valid testsignal. For example, if device 302 is handled and/or moved during thePCV test, the test may be declared invalid because movement of device302 by the user may obfuscate the impulse response of device 302 tovibrations generated by electromechanical transducer 310. Accordingly,device processor(s) 306 can determine whether the output signal of theaccelerometer is a valid test signal based on whether the motionsignal(s) indicate movement of device 302 when the output signal isgenerated. For example, if the motion signal(s) indicate movement of thedevice 302 occurred during the PCV test period, PCV test application 314can revert to stage 504. More particularly, the PCV test can berescheduled to a later time.

At operation 606, device processor(s) 306 can determine whetherprotective case 200 is mounted on device 302 based on the output signalreceived from sensor(s) 312 in response to the vibration test pattern.For example, in response to determining that no movement of device 302occurred when the output signal was generated, device processor(s) 306can use the output signal to draw conclusions about whether an impulseresponse of device-case system 100 represented by the output signal isindicative of a protected device.

Referring to FIG. 7, a graphical view of a test output signal generatedin response to a test input force and a baseline output signal generatedin response to a baseline input force is shown in accordance with anaspect. Notably, the test input force can provide the same vibrationalinput force as the baseline input force. A test output signal 702generated by sensor(s) 312 of device 302, when viewed in the timedomain, can approximate a sinusoidal pattern over the PCV test. Notably,the depicted profile may represent motion in along a single principalaxis, however, sensor(s) 312 may generate several output signalsrepresenting additional principal axes. Each output signal can be usedto make determinations as described below. The sinusoidal profilecorresponds to mechanical vibrations of electromechanical transducer 310when driven by the input signal. In fact, a time domain graph of asinusoidal vibration input force may be substantially similar to testoutput signal 702 illustrated in FIG. 7, with the exception of havingdifferent amplitude scaling (and being time shifted). In an aspect,device processor(s) 306 can use comparisons between time domain contentof output signal 702 and time domain content of a predetermined impulseresponse signal to determine whether device 302 is protected. Asdescribed below, however, comparisons between frequency domain contentof output signal 702 and the predetermined impulse response signal mayinstead be used by processor(s) 306 to determine whether device 302 isprotected. A baseline output signal 704 can be generated by sensor(s)312 of device 302, and when viewed in the time domain, can approximate asinusoidal pattern over the PCV test. The baseline output signal 704 canbe generated by sensor(s) 312 of device 302 when device 302 is in eitherof two configurations. More specifically, the baseline output signal 704can be generated by sensor(s) 312 of device 302 when device 302 is in anunprotected configuration as a stand-alone device or alternatively in aprotected configuration as part of a device-case system 100.

Referring to FIG. 8, a graphical view of a comparison between thefrequency domain representation of a test output signal 702 (shown inFIG. 7) and the frequency domain representation of a predeterminedbaseline output signal 704 indicative of an unprotected device is shownin accordance with an aspect. The waveforms shown in FIG. 8 canrepresent comparative data that device processor(s) may use to perform afirst level verification of protective case usage. As described above, apredetermined impulse response signal 802 can be generated from“stand-alone” accelerometer time domain data collected during stage 502of the PCV test application execution. A baseline output signal 704(shown in FIG. 7) can be generated by sensor(s) 312 of device 302 inresponse to the baseline input signal. The baseline output signal 704can be generated in the time domain, and device processor(s) 306 canapply an FFT algorithm to the time domain data to generate thepredetermined impulse response signal 802. The predetermined impulseresponse signal 802 corresponds to an unprotected device 302. Deviceprocessor(s) 306 can apply an FFT algorithm to the time domain data oftest output signal 702 (shown in FIG. 7) to determine the frequencycontent of test output signal 702 generated at operation 604. Thefrequency content of test output signal 702 can be termed a test datafrequency response spectrum.

In an aspect, device processor(s) 306 are configured to perform levelone verification to determine whether any type of protective case 200 ismounted on device 302 based on whether test data frequency responsespectrum 702 matches predetermined impulse response signal 802 for anunprotected device 302. Device processor(s) 306 can perform the firstlevel of verification by comparing the test data frequency responsespectrum 702 to predetermined impulse response signal 802. The firstlevel of verification can verify whether any type of protective case,e.g., a generic case such as a thin case skin, a more robust case, etc.,is mounted on device 302. More particularly, the properties of aprotective case that determine a profile of the frequency content ofvibration data recorded by the accelerometer of device 302 includes aweight of protective case 200, a geometric size and shape of protectivecase 200, or properties of materials used in the manufacture ofprotective case 200. When any type of protective case 200 is mounted ondevice 302, the inherent mechanical properties of the case will absorbenergy and resonate energy when subjected to vibrational stimulus, andthus, the impulse response of device-case system 100 will differ fromthe predetermined impulse response of a standalone device 302. Bycomparing the frequency response spectrum of the device 302 under testwith the known frequency response spectrum of a standalone device 302, adifference in the spectra (not matching) can indicate that the device302 under test is protected by some case, even if the exact model of thecase is unknown. The difference in the spectra can be a difference inthe peak frequency or a difference in amplitude of the peak frequency.Additionally, the difference in the spectra can be observed in theresults of waveform calculations such as power spectral density or rootmean square. Accordingly, device processor(s) 306 determining if testdata frequency response spectrum 702 matches predetermined impulseresponse signal 802 for an unprotected device 302 can identify amismatch in the test and reference profiles to determine that the firstlevel verification result is a PASS value. By contrast, if the frequencyresponse spectrum of the device 302 under test is identical or similarto (matching within a predetermined tolerance) the known frequencyresponse spectrum of a standalone device 302, the match indicates thatthe device 302 under test is unprotected. Accordingly, deviceprocessor(s) 306 can determine that the first level verification resultis a FAIL value.

Referring to FIG. 9, a graphical view of a comparison between a testoutput signal and a baseline impulse response indicative of a protecteddevice is shown in accordance with an aspect. The waveforms shown inFIG. 9 can represent comparative data that device processor(s) may useto perform a second level verification of protective case usage. Asdescribed above, a predetermined impulse response signal 802 can begenerated or retrieved by device processor(s) 306 during stage 502 ofthe PCV test application execution. For example, impulse response datarepresenting predetermined impulse response signal 802 of a referencedevice-case system 100 can be stored in system memory 308, e.g., in anin-app library. Device processor(s) 306 can retrieve the impulseresponse data corresponding to the device and protective caseinformation entered during installation and configuration of PCV testapplication 314. Accordingly, device processor(s) 306 can accessfrequency domain data representing an impulse response of a similar oridentical device-case system to the same input force 406 applied todevice 302 during the PCV test. Additionally, device processor(s) 306can apply an FFT algorithm to the time domain content of test outputsignal 702 (shown in FIG. 7), generated at operation 604, to determinethe test data frequency response spectrum.

In an aspect, device processor(s) 306 are configured to determinewhether protective case 200 is mounted on device 302 based on whetherthe frequency content of test output signal 702 matches predeterminedimpulse response signal 802 for a protected device 302. Deviceprocessor(s) 306 can perform the second level of verification bycomparing the test data frequency response spectrum 702 to frequencycontent of predetermined impulse response signal 802. The second levelof verification can verify whether a particular protective case, e.g., aprotective case having the same brand/model as was entered during stage502, is mounted on device 302. More particularly, when test datafrequency response spectrum is the same or similar to (matching within apredetermined tolerance) the expected impulse response 802 for a similardevice-case system, device-case system 100 can be assumed to be the sameas the reference device-case system. This result is illustrated in FIG.9, in which predetermined impulse response 802 matches test datafrequency response spectrum 702. Accordingly, device processor(s) 306can determine that the second level verification result is a PASS value.By contrast, if the frequency response spectrum of the device 302 undertest is different than (not matching) the expected impulse response 802,device processor(s) 306 can determine that the second level verificationresult is a FAIL value.

Referring again to FIG. 6, device processor(s) can perform a third levelof verification by verifying that the digital ID tag 206 on protectivecase 200 has an expected identifier. The identifier of digital ID tag206 can be entered or read during stage 502, as described above. Theidentifier that is read from digital ID tag 206 during the configurationof PCV test application 314 is a reference identifier. Moreparticularly, the reference identifier is an expected value of theidentifier at any point after configuration and registration. Forexample, if an owner of device 302, e.g., an employer, installsprotective case 200 having the reference identifier on device 302 priorto issuing device 302 to a user, e.g., an employee, the employer mayexpect that any time the NFC tag 206 on protective case 200 is queriedthereafter, the identifier would match the initial identifier value. Anydifference in the identifier values may indicate that the employee haschanged the protective case 200 to a different (and potentiallyimpermissible) protective case 200. When no digital ID tag 206 ispresent on protective case 200, e.g., when protective case 200 is ageneric case that does not include digital ID tag 206, the third levelof verification can be omitted by PCV test application 314. When digitalID tag 206 is present on protective case 200, however, the third levelof verification can be performed.

At operation 608, RF transceiver 350 of device 302 reads the identifierstored on digital ID tag 206 of protective case 200. Device processor(s)306 can therefore obtain both the test identifier and the referenceidentifier entered at stage 502. At operation 610, device processor(s)306 can determine whether the test identifier matches the referenceidentifier. More particularly, device processor(s) 306 can compare thetest identifier read by RF transceiver 350 during the PCV test to theexpected reference identifier value determined during configuration ofPCV test application 314. In an aspect, when the test identifier matchesthe reference identifier, device processor(s) 306 can determine that thethird level verification result is a PASS value. By contrast, when thetest identifier does not match the reference identifier, deviceprocessor(s) 306 can determine that the third level verification resultis a FAIL value.

One or more of the first level, second level, or third levelverification sequences described above may be combined to generate amore rigorous verification. For example, the third level verificationcan be combined with the second level verification to provide anincreased level of confidence that device 302 is being protected by anexpected protective case 200. More particularly, when the results of thedigital identifier code verification and a second level frequencyresponse spectrum comparison are both PASS values, then a heightenedlevel of verification can be provided by device processor(s) 306.Similarly, the second level verification can be combined with the firstlevel verification to provide an increased level of confidence thatdevice 302 is being protected by a protective case 200 having a similardegree of impact protection as the expected protective case 200.

Referring again to FIG. 5, at stage 508, PCV test application 314 canperform PCV test recording and/or reporting functions. Moreparticularly, after determining a presence or absence of protective case200 on device 302, PCV test application 314 can record the PASS/FAILtest values for each verification level in system memory, e.g., indevice memory 308. Furthermore, device 302 can transmit the test valuesto remote server 304 for recording and storage in server memory 322,e.g., in a database stored on remote server 304. A database softwareapplication running on remote server 304 can maintain records of the PCVtest values. The database software application can maintain a record ofall PCV test PASS and FAIL values for all three levels of verificationfrom each PCV test executed by device processor(s) 306.

In an aspect, PCV test results are reported to one or more interestedparties. For example, device processor(s) 306 can present a notificationwindow on the display of device 302 to the user. For example, thenotification window can include an alert indicating that the PCV testfailed because an expected protective case 200 was not detected. If theuser believes that the failure was an error, PCV test application 314can allow the user to initiate a new PCV test to generate a PASS valuethat can override the previous FAIL value.

RF communication circuitry 316 of device 302 can report PCV test resultsto one or more third parties. For example, when PCV test application 314is on a company-owned device 302, a PCV test FAIL value can be reportedto a responsible asset administrator of the company via email or SMStext. Similarly, when PCV test application 314 is on a device 302 thatis insured by an insurance company, a PCV test FAIL value can bereported to the insurance company via email or SMS text. When theinsurance company has insured device 302 under an insurance policy at areduced rate, the insurance company may use the reported test values asevidence that the user has broken the terms of the policy requiringdevice 302 to be kept inside of a specific protective case 200, and theinsurance company may terminate or increase the charged rate of thepolicy, accordingly.

It will be appreciated that PCV test results may be reported to theinterested parties by remote server 304. For example, the company thatowns device 302 and/or the insurance company that insures device 302 canregister with an information service provided by remote server 304.Remote server 304 can relay test results automatically or in response torequests from the registered third parties.

At stage 510, PCV system 300 can generate a PCV test report. The PCVtest report can be a summary of test results of verified protected caseusage over a specified period of time, e.g., weeks, months, or years.The report can be generated by remote server 304 or device 302. Moreparticularly, remote server 304 and/or device 302 can include a reportgeneration software application to generate the report using test dataresiding in memory of PCV system 300. For example, the report generationsoftware application can generate the PCV test report using datacollected and stored in server memory 322. The report generation can beresponsive to a request from an authorized party. For example, the userof device 302 may choose to request the PCV test report in preparationto offer device 302 for sale to potential buyers. The prospective buyerscan review the PCV test report to confirm the time duration that device302 has been protected by a case during its prior use.

Referring to FIG. 10, a pictorial view of a protective case verificationreport documenting protective case usage by a device is shown inaccordance with an aspect. The test report generation application cancreate and maintain copies of the PCV test report 1000 for distributionupon request. For example, when an authorized party requests the PCVtest report 1000, the test report generation application can email thePCV test report, e.g., as a .pdf document. The test report generationapplication may alternatively send a URL web link for the requestor toaccess the PCV test report or to use in on-line listings for referenceby potential purchasers. The potential purchasers can review an on-linecopy of the PCV test report residing on remote server 304 via the weblink.

As shown in FIG. 10, the PCV test report document 1000 can be dated, andcan identify the brand/model of protective case 200. Similarly,information about device 302, e.g., brand, model, serial number, etc.,can be provided in the report. The report can include verificationinformation 318 communicated by device 302 to remote server 304. Forexample, the PCV test report 1000 can document a level of verification1002 that protective case 200 is mounted on device 302. Moreparticularly, the report can indicate whether device processor(s) 306achieved a first level of verification 1002 (comparison to a standalonedevice), a second level of verification (comparison to a referencedevice-case system), and/or a third level of verification (digitalidentifier code verification). Verification information 318 representedin PCV test report can also include a percentage of time 1004 thatprotective case 200 is mounted on device 302. More particularly, thepercentage of time 1004 that the PCV test application 314 had PASSvalues for each of the supported levels of verification (level one,level two, and level three) during the report timeframe can be shown.For example, in the example of FIG. 10, device 302 was protected byprotective case 200 99.3% of the time between Jan. 5, 2017, and May 30,2017. Such verification information 318, and other verificationinformation generated as described above, can be valuable information.

In an aspect, PCV test application 314 is directed to reducing alikelihood that a counterfeit protective case will be used on device302. An unfortunate trend in the electronics industry can be found inthe proliferation of counterfeit products. Counterfeiters may attempt tobuild protective cases having cloned digital ID tags 206, e.g., NFC orBT tags, to make PCV test application 314 indicate that device 302 isprotected by a particular brand/model of protective case, when in factthe protective case is not the particular brand/model. Counterfeitersmay attempt to read the identifier of an authentic digital ID tag on anauthentic protective case, and then clone the digital ID tag. The cloneddigital ID tag can be placed on counterfeit protective cases and sold tounwary consumers.

In an aspect, PCV test application 314 can perform a dual-test format,which is capable of issuing a third level verification value of FAILwhen a protective case includes a cloned NFC tag 206. More particularly,the NFC tag identifier may indicate that the data string matches theexpected data string, however, the impulse response of the device-casesystem 100 including the counterfeit protective case may differ from theimpulse response of the reference device-case system. The difference canbe caused by manufacturing differences in the counterfeiting process,e.g., using low grade materials. Accordingly, the second levelverification value will be FAIL. By contrast, the impulse response willdiffer from a standalone device, and thus, the first level verificationvalue will be PASS.

In the dual-test format, a third level verification value of PASS isonly achieved when both the second level and the third levelverifications have PASS values. More particularly, if the NFC tag 206 iscloned accurately, the counterfeit case may achieve a third levelverification value of PASS, however, the second level verification valuewill be FAIL. As such, the highest level of verification 1002 for thedevice-case system 100 under test will be a first level of verification,indicating that device 302 is protected by a generic case. Additionally,as described above, the identifier in NFC tag 206 can be encrypted toreduce a likelihood that counterfeiters will successfully clone NFC tag206.

In an aspect, PCV test application 314 and or protective case 200 areconfigured to reduce a likelihood that a salvaged NFC tag will beinserted into a generic protective case to make PCV test application 314indicate that device 302 is protected by a particular brand/model ofprotective case, when in fact the protective case is not the particularbrand/model. A user may peel a self-adhesive NFC tag out of a genuineprotective case and then slip the salvaged NFC tag between their device302 and a generic protective case. In such case, PCV test application314 may read the NFC tag as indicating that the protective case is anexpected brand/model protective case, when in fact the protective caseis generic and potentially does not provide the expected level ofprotection to device 302.

The potential problem of a salvaged NFC tag thwarting PCV testapplication 314 may be mitigated by the dual-test format describedabove. More particularly, the salvaged NFC tag may cause PCV testapplication 314 to determine a third level verification value of PASS,however, the second level verification value will be FAIL because thegeneric case will not have the same impulse response as the expectedcase. Accordingly, the highest level of verification 1002 will revert toa first level of verification.

To further reduce a likelihood that a user will successfully salvage anNFC tag, NFC tag 206 may be tamper-resistant. In an aspect, NFC tag 206can include a seam that tears or breaks when removed from protectivecase 200. For example, the seam may be pre-stressed, weakened, orotherwise formed with a tear strength that is less than a force requiredto remove NFC tag 206 from protective case 200. Accordingly, when a userattempts to peel NFC tag 206 from wall 202 of protective case 200, theseam may tear, which can cause damage to the antenna windings of the NFCtag 206. In an aspect, the windings may run across the seam, making itmore likely that the winding will be damaged when the seam tears. Whenthe windings are damaged, salvaged NFC tag 206 becomes inoperable.

In an aspect, a likelihood of removing digital ID tag 206 fromprotective case 200 may be reduced by encasing NFC tag 206 within wall202 of protective case 200. For example, as described above, NFC tag 206can be embedded within the plastic of protective case 200 during aninjection molding fabrication process. In an aspect, digital ID tag 206is encased in an offset position, relative to a thickness of wall 202.More particularly, wall 202 of protective case 200 may have a thicknessextending from an exterior surface to an interior surface. The exteriorsurface may be a surface facing the surrounding environment, and theinterior surface may be a surface facing and/or in direct contact withdevice 302 when the device is installed in protective case 200. NFC tag206 may similarly have an outer surface and an inner surface, each ofwhich are parallel to the exterior and interior surfaces of wall 202. Inan aspect, a distance between the outer surface of NFC tag 206 and theexterior surface of wall 202 may be greater than a distance between theinner surface of NFC tag 206 and the interior surface of wall 202. Moreparticularly, NFC tag 206 may be embedded in wall 202 at a location thatis offset toward the interior surface of wall 202. This offset positionof NFC tag 206 can reduce RF field attenuation between NFC reader 350 ofdevice 302 and NFC tag 206 of protective case 200. The reducedattenuation can increase an input voltage that will be generated by thewinding of NFC tag 206, making the tag readable by NFC reader 350.

In an aspect, PCV test application 314 and or protective case 200 areconfigured to reduce a likelihood that a salvaged NFC tag 206 will betaped to the back of a standalone device to make PCV test application314 indicate that device is protected by a particular brand/model ofprotective case 200, when in fact the device 302 is unprotected. If auser gained access to a used genuine protective case 200 and peeled theauthentic NFC tag 206 off of wall 202, the user could tape NFC tag 206directly to the back of a device 302 to simulate a protected device 302.More particularly, taping NFC tag 206 to a standalone device may trickPCV test application 314 into incorrectly verifying that the device isprotected.

The dual-test format described above may mitigate the salvaged NFC tagproblem. More particularly, second level verification of the protectivecase 200 will fail even if the third level verification passes.Furthermore, during the reading of the identifier during stage 502 andor during the PCV test, device processor(s) 306 can determine a signalstrength received from NFC tag 206 when the tag is queried for theidentifier. Device processor(s) 306 may further determine whether thesignal strength is within a predetermined tolerance. When device 302 isunprotected, e.g., when protective case 200 is not mounted on device302, the electromagnetic field lines (flux) emanating from the antennaof NFC reader 350 may impart a different signal strength into theantenna windings of NFC tag 206. The different signal strength may alsoresult from the salvaged tag being taped to a different locationrelative to the transceiver antenna than would be the case in anauthentic protective case 200. This difference in the signal strengthparameter can be detected by device processor(s) 306 and used todetermine that NFC tag 206 is not in or on an authentic protective case200. The result may be a determination that device 302 is unprotectedthus test results are FAIL for all three levels of verification.

It will be appreciated that PCV test application 314 can includeadditional or modified features as compared to the features describedabove. For example, PCV test application 314 may track protective caseusage as described above, however, the application can allow the user tochange to a different protective case 200. For example, if a userchanges to a different make/model of protective case 200, PCV testapplication 314 can report the change to the database on remote server304. For instance, if the user upgrades their protective case 200 from athin case skin (only capable of first level verification) to a moredurable case that supports second level verification and/or third levelverification, the verification information 318 can be communicated fromdevice 302 to remote server 304 for inclusion in the PCV test report.

In an aspect, the sensor(s) 312 used to generate output signal 702 inresponse to input vibrations may include a microphone. Furthermore, theelectromechanical transducer 310 that generates the input vibration mayinclude a speaker. In some instances, device 302 may not include avibration motor and/or an accelerometer. In either case, during stage502, PCV test application 314 may be configured to substitute audio dataanalysis for accelerometer data analysis. At operation 602, deviceprocessor(s) 306 can drive an audio speaker to generate an input force406 (which in turn generates acoustic vibrations). At operation 604, theaudio microphone can detect the acoustic vibrations, and in response,generate an output audio signal. In other words, the speaker cangenerate an input audio pattern and the microphone can record an outputaudio pattern corresponding to the input audio pattern. The recordingcan occur concurrently, e.g., simultaneously, with the playback ofaudio.

In an aspect, the audio input signal includes audio tone segments ofdiffering frequency and differing amplitudes. Device 302 may haveseveral speakers, e.g., a left speaker and a right speaker, and theaudio input signal may have respective audio channels to independentlydrive one or more of the left speaker or the right speaker. For example,sound may be emitted by only one of the left speaker or the rightspeaker when device processor(s) 306 play back the audio input signal.In another aspect, when device 302 supports several microphones, e.g., aleft microphone and a right microphone, the audio input signal may becross-configured to utilize the stereo microphone functionality incombination with stereo speakers to record more complex audio outputsignals 702.

In an aspect, during a test, the audio output signal 702 can be recordedin the time domain and processed using an FFT algorithm to generate afrequency response spectrum that represents a test data frequencyresponse spectrum 702 (shown in FIG. 8) of device-case system 100 whenan acoustic input is applied to the system. Accordingly, comparisonsbetween the test data frequency response spectrum and a standalonedevice or reference device-case system spectra can be made to determinewhether protective case 200 is mounted on device 302 (operation 608).

Other variations in the input signal used to generate output signal 702for verifying protective case usage may be contemplated. For example, inlieu of a vibration motor to create the input force 406, the input forcemay instead result from an externally applied impact. Device 302 may nothave an internal vibration motor (or the equipped motor may be too weakto generate an adequate input force 406), and thus, the input force usedto generate a corresponding output signal may come from another inputsource. In an aspect, PCV test application 314 can prompt the user totap device 302 on an external surface to begin the PCV test. Forexample, device processor(s) 306 can present a start button on thedisplay of device 302, and after the user taps the button, the user cantap a corner of device 302 on a hard, flat surface. Sensor(s) 312 ofdevice 302 can detect the vibrations resulting from the impact, andgenerate the test output signal 702 as a time domain representation ofthe shock. Device processor(s) 306 can determine, based on the testoutput signal 702, whether protective case 200 is mounted on device 302by comparing the frequency response spectrum to the standalone device orreference device-case system spectra. The comparison can indicatewhether protective case 200 is mounted on device 302 (operation 606).

Impacts from accidental drop events may also be used as the input force406 of the PCV test. Device processor(s) 306 can monitor sensor(s) 312in real-time and record impact data from real life accidental dropevents. For example, processor(s) 306 can determine that device 302 isin a free fall state based on motion data from sensor(s) 312. When thefree fall state is followed by an impact, processor(s) 306 can usemotion data preceding the impact and the impact data to determinewhether device 302 was in protective case 200 at the time of the drop.

In an aspect, device processor(s) 306 can use orientation data fromsensor(s) 312 to determine an orientation of device 302 at the time ofimpact. For example, device processor(s) 306 can determine whetherdevice 302 landed on a corner or on a back surface based on theorientation data. Similarly, device processor(s) 306 can determine aheight from which device 302 was dropped based on an elapsed duration ofthe free fall state. The drop height can be used to determine amagnitude of the impact force and/or a velocity at impact. By combiningthe information about the orientation and the velocity at impact, theresulting accelerometer impact measurements for each drop event can bedetermined and recorded, e.g., written to a database on remote server304. The impact measurements can represent a shock dampingcharacteristic of device-case system 100 for the particular drop heightand impact orientation. Remote server 304 can validate the impactmeasurements against predetermined impact measurements for similardevice-case systems. For example, the impact measurements can becompared to impact measurements collected for reference device-casesystems dropped from similar (within a tolerance) heights and at similar(within a tolerance) impact orientations. The comparison may be made bydevice processor(s) 306 or by server processor(s) 320. For example, PCVtest application 314 may periodically download baseline statisticalmodeling factors representing impact measurements that were calculatedbased on a large set of data from drop events experienced by otherdevice-case systems having the same device in the same protective case.The downloaded factors may be used for comparison. Alternatively, serverprocessor 320 can receive the impact measurements from the otherdevice-case systems and store them in the database for comparison toimpact measurements received from device 302. Based on such comparisons,PCV test application 314 can verify that the second level verificationis a PASS value when the impact measurements from device 302 match thebaseline statistical modeling factor, or a FAIL value when the impactmeasurements from device 302 do not match the baseline statisticalmodeling factor.

In an aspect, a timer feature may be implemented such that any attemptto read digital ID tag 206 can trigger an update to the timer functionwhich records a duration of time that device 302 is installed insideprotective case 200. At stage 502, when NFC reader 350 queries NFC tag206, and receives the identifier, PCV test application 314 can start atag duration timer. PCV test application 314 can record the start date,start time, and start GPS coordinates. While the tag duration timer isrunning, PCV test application 314 can periodically access the NFC readfunction of device 302 to verify that protective case 200 remainsinstalled on device 302. More particularly, NFC reader 350 can becontrolled to read the identifier from NFC tag 206 periodically whilethe tag duration timer is active. The periodic attempts to access datain NFC tag 206 may be triggered by a periodic timer function. In anaspect, the periodic access attempts are triggered by software functionsthat can monitor and/or make calls to certain operating systemfunctions. For example, one or more NFC tag duration timer functions mayreside in the operating system of device 302. As an example, an NFC tagduration timer read function may be built into the operating system. Toimplement the periodic reading of data from NFC tag 206, PCV testapplication 314 may make periodic calls to the NFC tag duration timerfunction(s) noted above. Alternatively, the NFC read functionssupporting the tag duration timer can be built into the operating systemand they may also independently periodically monitor for the presence ofNFC tag 206. In the event that the NFC tag duration timer read functiondetermines NFC tag 206 is no longer within range of NFC reader 350, theNFC tag duration timer read function can notify PCV test application314. Upon notification by the NFC read functions in the operatingsystem, PCV test application 314 can stop the tag duration timer andrecord the end date, end time, and end GPS coordinates. PCV testapplication 314 can transmit the start and end information to remoteserver 304 for use in determining a percentage of time 1004 that device302 was protected.

Operating system calls of device 302 may be used to initiate the PCVtest. At stage 504, a start test command may be implemented in responseto monitoring one or more calls being made to the operating systemfunctions. For example, if the device processor(s) 306 observe operatingsystem calls being made to establish an NFC communication link withwireless charging plate 414, device processor(s) 306 may initiate aspecial code sequence with the goal of starting and completing the nextPCV test while device 302 is resting on wireless charging plate 414. Theaccuracy and repeatability of the PCV test may be enhanced by performingthe PCV test while device 302 is resting on a surface of known physicalproperties, such as the surface of a particular brand/model of wirelesscharging plate 414. Accordingly, starting the PCV test in response tothe NFC communication link being established can result in improved testaccuracy. In an aspect, PCV test application 314 may reference adatabase stored in system memory 308, which details the known physicalcharacteristics and properties of the contact surface of one or morewireless charging plates on the market. For example, the wirelesscharging plates may be several of the best-selling charging accessories.Accordingly, frequency response spectra used by PCV test application 314during the PCV test, e.g., at operation 606 and/or during second levelverification, can further account for specific mechanical surfaceinteractions between device-case system 100 and wireless charging plate414 on which the system rests. In an aspect, PCV test application 314may reference a database stored in system memory 308, which containspredetermined baseline frequency response spectra for device-case system100 resting on different make(s)/model(s) of wireless charging plate414.

In an aspect, digital ID tag 206 can store information in addition tothe identifier. For example, NFC tag 206 may encode information that canbe used by device 302 to adjust settings of the PCV test. The settingsmay include a frequency, amplitude, or duration of the input signal thatis used to drive electromechanical transducer 310. For example, duringstage 502, NFC reader 350 can read setting information from NFC tag 206,and PCV test application 314 can be configured to with the settings.When PCV test begins, device processor(s) 306 can deliver thepredetermined input signal (which is specific to the particularprotective case 200) to cause electromechanical transducer 310 togenerate a predefined vibration. For example, the predefined vibrationmay be at a resonant frequency of the protective case 200. Accordingly,the settings of PCV test application 314 may be configurable based ondata stored on NFC tag 206.

Referring to FIG. 11, a block diagram of a system having a digital IDtag for verifying protective case usage is shown in accordance with anaspect. Device-case system 100 can include device 302, e.g., asmartphone device, having the components described above. For example,device 302 can be a smartphone device having the components describedwith respect to FIG. 4. Furthermore, device-case system 100 can includedigital ID tag 206 mounted on protective case 200 as described above.Protective case 200 can be mounted on device 302 (not shown).

In an aspect, RF transceiver 350 can utilize the NFC protocol tocommunicate with an NFC-based digital ID tag 206 to implement any of theoperations described above. In some cases, when NFC tag 206 is thenearest tag to NFC reader 350, the communication link between device 302and NFC tag 206 may prevent NFC reader 350 from recognizing other NFCtags in the vicinity. More particularly, the NFC tag 206 withinprotective case 200, which is within the readable distance of NFC reader350, may permanently limit the NFC tag reading capability of NFC reader350 to reading only NFC tag 206. This assignment may preventcommunication with other nearby tags, and may interfere with theusability of mobile device 302 in some situations. For example, the usermay be unable to interact with an alternate NFC tag. Accordingly, in anaspect, NFC tag 206 can be a dormant NFC tag that can be selectivelyswitched from a dormant state, e.g., a state in which NFC tag 206 cannotcommunicate information to NFC reader 350, to an active state, e.g., astate in which NFC tag 206 can communicate information to NFC reader350.

The dormant NFC tag 206 can be incorporated into device-case system 100in the manners described above. For example, the dormant NFC tag 206 canbe insert molded into protective case 200 or mounted on a wall ofprotective case 200. In an aspect, the dormant NFC tag 206 includeselectronic hardware that allows the tag to remain dormant, e.g.,non-functional, until it is activated by device 302. Device 302 canperform operations, e.g., device processor(s) 306 can executeinstructions stored in device memory 308 (FIG. 3) to cause NFC tag 206to awaken and/or put NFC tag 206 to sleep. The structure of dormant NFCtag 206 is described below in combination with a functional sequenceused by device-case system 100 to wake NFC tag 206 from the dormantstate, initiate and complete an NFC read operation of the NFC tag 206 byNFC reader 350 when NFC tag 206 is in the active state, and put NFC tag206 back to sleep, e.g., place NFC tag 206 into the dormant state.

In an operation, a software application of device, e.g., PCV testapplication 314, can initiate a read process in which NFC reader 350will read relevant data from memory of the NFC tag. For example, theread process can be performed as part of operation 608 to support thethird level verification that device 302 is protected by protective case200. NFC tag 206 can initially be in the dormant state. In the dormantstate, an NFC tag antenna 1118 of NFC tag 206 can receive NFC radiofrequency (RF) energy from NFC reader 350. The RF energy can generate anelectrical current in the tag antenna that is communicated to a voltageregulator 1112 used to power components of NFC tag 206. Moreparticularly, a switch, e.g., a double pole-double throw switch 1116,can connect the NFC tag antenna 1118 to the voltage regulator 1112 inthe dormant state. The default position of switch 1116 in the dormantstate can be termed position A, and as shown, when the switch is inposition A the switch can transfer electrical energy from the NFC tagantenna 1118 to the voltage regulator 1112.

The voltage regulator 1112 can have a voltage output at the commoncollector that powers several tag components used to monitor anactivation signal 1120 from device 302, and to switch NFC tag 206 to theactive state when the activation signal 1120 is detected. Moreparticularly, the voltage regulator 1112 can power an activation circuitwhen NFC tag 206 is in the dormant state.

In an aspect, NFC tag 206 includes the activation circuit to detect theactivation signal. The activation circuit includes an electromechanicaltransducer 1100, an amplifier 1102 (optionally), and a wake logiccircuit 1104. The activation signal can be generated by device 302 usingthe actuation modes described above. More particularly, PCV testapplication 314 can cause device processor(s) 306 to generate avibration event by actuating electromechanical transducer 310, e.g., avibration motor, a haptic engine, or a speaker of device 302. Theactuated transducer can emit vibration energy in the form of soundand/or physical vibrations. The activation signal 1120 can be termed a“wake signal” when the activation signal is intended to wake NFC tag 206from the dormant state. The activation signal 1120 can be transmittedfrom device 302 to NFC tag 206 through physical contact, e.g., whendevice 302 is in contact with protective case 200 that contains NFC tag206, or through acoustic coupling, e.g., when device 302 emits soundsacross a gap between the device housing and protective case 200.Regardless of the mode of transmission, the activation signal 1120 isinput to NFC tag 206 as a mechanical vibration at the tag surface.

It will be appreciated that physical coupling and/or acoustic couplingbetween protective case 200 and device 302 can be facilitated through astructure of protective case 200. For example, protective case 200 mayinclude a recess in an inner wall adjacent to digital ID tag 206 suchthat the surface of the inner wall is separated from a back wall ofdevice 302 by an air gap. Conversely, protective case 200 can include aboss, column, raised feature, etc., on the inner wall over digital IDtag 206 such that the raised area ensures contact between protectivecase 200 and device 302. Accordingly, the combination of protective case200 and the device housing of NFC tag 206 can facilitate the efficienttransmission of the wake signal vibration from electromechanicaltransducer 310 of device 302 to the electromechanical transducer 1100 ofNFC tag 206.

The electromechanical transducer 1100 of NFC tag 206, e.g., anaccelerometer, a piezoelectric transducer, or other transducerconfigured to convert vibrations into electrical signals, can receivethe mechanical vibration input from device 302. In an aspect, theelectromechanical transducer 1100 is a piezoelectric transducer thatreceives the wake signal 1120 energy and converts the energy into anelectrical signal. The piezoelectric transducer 1100 can be a relativelyinexpensive transducer that is sensitive to vibration, and thus,suitable to the dormant NFC tag application. For example, thepiezoelectric transducer can include a low cost quartz crystal disc toconvert vibrational energy into electrical energy. The electrical signalrepresenting the wake signal 1120 can be transmitted from thepiezoelectric transducer 1100 to an amplifier 1102.

The amplifier 1102 can be an operational amplifier configured to amplifythe activation signal 1120 received from the piezoelectric transducer1100. For example, the activation signal may be output by piezoelectrictransducer 1100 proportional to the vibration of the input wake signal1120, and the amplifier 1102 can amplify the signal by a gain factor.After amplifying the wake signal 1120, the amplifier can transmit theamplified signal representing the wake signal to a wake logic circuit1104. In an aspect, the amplifier 1102 can have a ground connection anda signal connection with the wake logic circuit 1104.

The wake logic circuit 1104 can include analog and digital circuitsconfigured to identify a pattern in the received amplified signal. In anaspect, the wake logic circuit 1104 can include discrete and integratedlogic, e.g., logic circuits that are fabricated from both discretecomponents and integrated logic chips. The wake logic circuit 1104 caninclude a comparator circuit, a threshold detector circuit, a patternrecognition logic circuit, etc., to determine whether the receivedamplified signal matches a predetermined pattern. The predeterminedpattern can indicate that the vibrations received by theelectromechanical transducer are the wake signal 1120 generated bydevice 302. For example, the wake signal 1120 provided by device 302 maybe a sequence of one or more vibration pulses of a predetermined number.Each pulse may have a predetermined duration of vibration, and adjacentpulses can be separated by a predetermined duration of non-vibration.The periods of peaks and valleys in the pulse sequence can represent abinary input, e.g., a high signal of a predetermined duration followedby a low signal of a predetermined duration followed by a high signal ofa predetermined duration, and so on. In an aspect, the wake logiccircuit 1104 monitors the amplified signal for the predeterminedsequence. That is, the wake logic circuit 1104 can decode and identifythe wake signal pattern 1120 within the amplified signal.

The wake logic circuit 1104 can include one or more filters to processthe wake signal 1120. For example, a band-pass filter or a low-passfilter can be used to filter the wake signal 1120 based on an amplitudeor frequency of the signal. More particularly, the input vibration ofthe wake signal 1120 may have a predetermined frequency, and one or morefilters in the wake logic circuit 1104 can be used to only passactivation signals having corresponding frequencies. Accordingly, thefilters can clean the input signal as a pre-processing operationprecedent to determining whether the input signal matches thepredetermined sequence of pulses.

In an aspect, the wake logic circuit can communicate with atimer/control circuit. Communication between the timer/control circuit1106 and the wake logic circuit 1104 can be two-way communication suchthat communication signals pass both ways between the tag components.For example, when the wake logic circuit 1104 detects the predeterminedpattern indicating that device 302 has provided the activation signal1120 to NFC tag 206, the wake logic circuit 1104 can send an enablesignal to trigger an operation by the timer/control circuit 1106.Similarly, when the NFC read process is complete, the timer-controlblock 1106 can send a reset signal to the wake logic circuit 1104, asdescribed below.

The timer-control block 1106 can start a timer function in response toreceiving the enable signal from the wake logic circuit 1104. Moreparticularly, the timer functions can include actuating the switch 1116to connect the NFC tag antenna 1118 to an NFC integrated circuit (IC)1114. More particularly, timer-control circuit 1106 can alter a signalon the control line to the switch 1116 to cause the switch to move(physically or electronically) to a position B (not shown). At positionB, the switch 1116 contacts connect the NFC antenna 1118 to the NFC IC1114. The switch 1116 may include one or more transistors as switches toconnect the NFC IC 1114 to the NFC tag antenna 1118. When the switch1116 is moved from the voltage regulator contacts to the NFC ICcontacts, NFC tag 206 is still in the dormant state and will nottransition to the active state until the signal on the enable line toNFC IC 1114 is activated. Accordingly, the NFC tag antenna 1118 canpower and/or communicate voltage to the NFC IC 1114.

When the timer/control circuit 1106 is enabled, and switch 1116 has beenmoved to position B, the circuit can then activate the signal on theenable line connected to the NFC IC 1114. The signal on the enable linecan be asserted after actuating the switch 1116 to move to position B toconnect the NFC tag antenna 1118 to the NFC IC 1114. When the enableline is activated, the NFC IC 1114 can be active and can respond torequests for data content sent by NFC reader 350. More particularly, NFCreader 350 can issue a read command, for example, to perform a thirdlevel verification by reading an identifier from the dormant NFC tag206. The NFC IC 1114 of the active tag can respond to the request bytransmitting the contents of a tag memory to NFC reader 350. Forexample, NFC IC 1114 can send the identifier and/or other informationstored in the tag memory to NFC reader 350 via the NFC tag antenna 1118.

In an aspect, the timer/control circuit 1106 can be connected to groundthrough an analog circuit, e.g., an RC circuit 1108, having a decayrate. For example, a voltage value of RC circuit 1108 can have anexponential decay that decreases from the voltage of the commoncollector when the switch 1116 is in position A to a lower thresholdvoltage within a decay period, e.g., within 1-2 seconds, when the switch1116 is in position B. The decay period represents a period within whichNFC reader 350 can read a unique identifier and/or payload informationfrom the NFC IC 1114. More particularly, the active state of NFC tag 206may last for the decay period, while the timer/control circuit 1106ensures sufficient energy is stored to activate the enable line and thencontrol switch 1116 to move back to position A to receive external powerfor operating the voltage regulator 1112. The lower threshold voltagecan correspond to the minimum energy required to actuate the switch 1116to move back to position A. Thus the active state can occur between thetime when the timer control circuit 1106 activates the enable line toNFC IC 1114 until the time when timer control circuit 1106 deactivatesswitch 1116 to move from position B back to position A. By contrast, thedormant state can occur between the time when switch 1116 is moved fromposition B back to position A until the time when timer control circuit1106 activates the enable line to NFC IC 1114.

During the active state, NFC reader 350 can receive the NFC tag data,e.g., operation 608. The received information can then be used by theone or more processors of device-case system, e.g., operation 610.Following receipt of the NFC tag data, PCV test application 314 cancause device processor 306 to end the NFC read request. Similarly, theNFC read attempt may end in response to the switch 1116 being reset toposition A when the timer/control circuit voltage drops to the thresholdvoltage. In either case, if the NFC read function was unsuccessful,device 302 can issue a new read request and wake signal 1120 to obtainthe relevant data from the NFC IC 1114.

When the RC circuit voltage reaches the predetermined voltage thresholdlow value, the timer/control circuit 1106 can put the NFC tag 206 backin dormant state causing NFC IC 1114 to end communication with the NFCtag antenna 1118 and NFC reader 350. More specifically, timer/controlcircuit 1106 can deactivate the control line to switch 1116 todisconnect the NFC tag antenna 1118 from the NFC IC 1114 and to connectthe NFC tag antenna 1118 to the voltage regulator 1112 at position A.NFC tag 206 can then be in the dormant state. In the dormant state, thewake circuit 1104 is powered by the NFC tag antenna 1118 withoutinterfering with communications between NFC reader 350 and other nearbyNFC tags. Furthermore, in the dormant state, the wake circuit canmonitor the output of the piezoelectric transducer 1100 for another wakesignal 1120 from device 302 indicating that NFC reader 350 is ready toperform an NFC read operation on NFC IC 1114.

In an aspect, the wake logic circuit 1104 may be reset each time NFC tag206 transitions from the active state to the dormant state. For example,as part of the reset function when the RC voltage level reaches the lowvoltage threshold and switch 1116 is moved back to position A, thetimer/control circuit 1106 can send a reset signal to the wake logiccircuit 1104, e.g., to trigger a reset function of the wake logiccircuit. The wake logic circuit 1104 may then be reset to monitor inputpatterns from the amplifier 1102, and thus, to identify the next wakesignal 1120 received by NFC tag 206 from device 302. Additionally, eachtime NFC tag 206 transitions from the active state to the dormant statethe timer control circuit 1106 de-asserts the enable line to NFC IC1114.

Referring to FIG. 12, a block diagram of a system having a dormant BTtag for verifying protective case usage is shown in accordance with anaspect. Device-case system 100 can include device 302, e.g., asmartphone device, having the components described above. For example,device 302 can be a smartphone device having the components describedwith respect to FIG. 4. Furthermore, device-case system 100 can includea dormant BT tag 206 mounted on protective case 200 as described above.Protective case 200 can be mounted on device 302 (not shown).

The dormant BT tag 206 can be incorporated into device-case system 100in the manners described above. For example, the dormant BT tag 206 canbe insert molded into protective case 200 or mounted on a wall ofprotective case 200. In an aspect, the dormant BT tag 206 includeselectronic hardware that allows the tag to remain dormant, e.g.,non-functional, until activated by a timer-control circuit 1206. DormantBT tag 206 can support a special timer function responsible for BTLE(Bluetooth Low Energy) broadcast data transmissions occurring veryinfrequently, e.g., only three or four times per day. In contrast,typical industry standard BTLE beacon ICs are designed to transmit 8,000to 150,000 broadcast events per day. By significantly decreasing thefrequency of BT beacon transmissions dormant BT tag 206 increasesavailable BT bandwidth on device 302 for other BT accessories and alsoincreases available processor bandwidth on device 302 by reducing thedata processing overhead associated with near constant BTLE broadcasttransmissions. The structure of dormant BT tag 206 is described below incombination with a functional sequence used by timer-control circuit1206 to wake BT tag 206 from the dormant state, initiate and complete abroadcast transmission of BT tag data to BT radio 350 of device 302 andthen put BT tag 206 back to sleep, e.g., place BT tag 206 into thedormant state.

In an operation, device processor(s) 306 can execute code from the PCVtest application 314 to configure the BT functions of the operatingsystem of device 302 to direct all BT beacon packets containing the PCVidentifier code to the PCV test application 314. Upon power up, timercircuit 1206 of dormant BT tag 206 can initiate a count-down timerwhereupon expiration timer circuit 1206 can then initiate an activationsequence resulting in BT data broadcast transmission of relevant datafrom BT tag 206 to BT radio 350. For example, the data broadcastfunction can be performed in support of operation 608 to evaluate thethird level verification that device 302 is protected by protective case200. BT tag 206 can initially be in the dormant state. In the dormantstate, an energy harvesting antenna 1200 of BT tag 206 can receive radiofrequency (RF) energy from active RF circuitry 316 in device 302 or inthe surrounding environment, e.g., cellular, WiFi, Bluetooth, NFC, orRFID. The RF energy can generate an electrical current in RF harvestingantenna 1200 that is communicated to voltage regulator 1112 and powermanagement IC 1202 and used to power components of dormant BT tag 206.More particularly, a switch, e.g., a double pole-single throw switch1212, can be used to connect the power management IC 1202 to theBluetooth (BT) IC 1214 in the active state. The default position ofswitch 1212 is open, and as shown, when the switch is in the openposition the switch does not transfer electrical energy from the powermanagement IC 1202 to the BT IC 1214, resulting in the BT tag 206 beingin the dormant state.

The voltage regulator 1112 can have a voltage output at the commoncollector that powers several tag components used to monitor a timercircuit, and to switch BT tag 206 to the active state when the timerexpiration signal is detected. More particularly, the voltage regulator1112 and power management IC 1202 can power an activation timer-controlcircuit 1206 when BT tag 206 is in the dormant state.

In an aspect, dormant BT tag 206 includes a timer-control circuit 1206which is responsible for both the count-down timer function and theactivation circuit functions. After voltage regulator 1112 and powermanagement IC 1202 have received adequate RF energy/voltage, and storagecapacitor 1204 has been adequately charged, power management IC 1202enables timer-control circuit 1206 to then begin decrementing the presetcount-down timer. The duration of the count-down timer can be preset atthe time dormant BT tag 206 is manufactured. Upon expiration of thecount-down timer the activation circuit verifies that the voltage statussignal from power management IC 1202 is true before executing the twocontrol functions that enable BT IC 1214 to transmit BT beacon datapackets. The first activation function carried out by the control logiccircuit can be to assert the control line to close double pole-singlethrow (DPST) switch 1212, to allow voltage to be applied to the BT IC1214. Following the voltage being applied to BT IC 1214, the secondactivation function carried out by the control logic circuit is theassertion of the enable line going to the BT IC 1214. Upon assertion ofthe enable line, BT IC 1214 powers on and begins executing boot-code andthen automatically transmits beacon data packets using BT antenna 1216.The transmitted beacon data packets are received by the BT radio 350 andin turn are passed on to the PCV test application 314. Aftertransmitting the first set of BT beacon data packets to BT radio 350, BTIC 1214 continues to transmit beacon data packets until timer/controlcircuit 1206 de-asserts the control line to DPST switch 1212. Thetimer-control circuit continues to monitor the decreasing voltage of RCcircuit 1208 for a voltage low threshold (VLT). Upon reaching the VLT,the timer-control circuit 1206 disables the BT IC 1214 by de-assertingthe enable line and then opens DPST switch 1212 by de-asserting thecontrol line.

In an aspect, a power management IC 1202 can communicate withtimer/control circuit 1206. Communication between the timer/controlcircuit 1206 and the power management IC 1202 can be two-waycommunication such that communication signals pass both ways between thetag components. For example, power management IC 1202 and timer-controlcircuit 1206 can both be reset through a mutual reset sequence each timeBT tag 206 transitions from the active state to the dormant state.Additionally, when power management IC 1202 detects storage capacitor1204 has reached a voltage level that exceeds a predetermined V_(min)(minimum operational voltage) the power management IC 1202 can activatethe enable control line to allow the timer-control circuit 1206 to poweron. Furthermore, the power management IC 1202 can output a voltagestatus signal that must be true when the count-down timer expires forthe timer-control circuit 1206 to be assured that there is enoughelectrical power available to successfully wake the dormant BT IC 1214and effect the successful transmission of BT beacon data packets. If thecount-down timer expires and the voltage status signal is false, thetimer-control circuit 1206 logic can reset the count-down timer andbegin a new count-down sequence. Additionally, after the BT beacon datapacket transmission has been completed and the voltage of the RC circuit1208 has decreased to the VLT, timer-control circuit 1206 can de-assertthe enable line to the BT IC 1214 and then de-assert the control line toopen DPST switch 1212 to disconnect power from the BT IC 1214.Furthermore, with the voltage of RC circuit 1208 reaching VLT (voltagelow threshold) the timer-control circuit 1206 can send a reset signal tothe power management IC 1202, as described below.

The timer-control circuit 1206 can start a count-down timer function inresponse to receiving the enable signal from the power management IC1202. Additionally, the timer-control functions can include actuatingthe DPST switch 1212 to connect the voltage outputs to a BT integratedcircuit (IC). More particularly, timer-control circuit 1206 can alter asignal on the control line to DPST switch 1212 to cause the switch tomove (physically or electronically) to a closed position (not shown). Atthe closed position, the switch contacts connect the voltage outputs ofa power management IC 1202 to the power input pins on a BT IC 1214. Theswitch may include one or more transistors as switches to connect apower management IC 1202 to a BT IC 1214. When the switch is moved tothe BT IC contacts and the enable line is activated, BT tag 206 is inthe active state. Accordingly, in the active state the power managementIC 1202 can power and/or communicate voltage to the BT IC 1214.

When the timer-control circuit 1206 is enabled, and the count-down timerexpires, and the voltage status signal is true, the circuit can actuatethe control line to DPST switch 1212 to connect the power management IC1202 to the BT IC 1214. After actuating the switch to connect the powermanagement IC 1202 to the BT IC 1214 the circuit can assert the enableline allowing BT IC 1214 to become active. When the enable line isasserted, the BT IC can be active and can transmit BT beacon datapackets to a BT radio 350. More particularly, BT reader 350 can receivethe BT beacon data packets and forward the packets to PCV testapplication 314, for example, to perform a third level verification byreading an identifier from the dormant BT tag 206. BT IC 1214 of BT tag206 is programmed such that after power up BT IC 1214 automaticallytransmits beacon packets containing the contents of a tag memory to BTradio 350. For example, BT IC 1214 can send the identifier and/or otherinformation stored in the tag memory to BT radio 350 via BT tag antenna1216.

In an aspect, the timer/control circuit can be connected to groundthrough an analog circuit, e.g., an RC circuit 1208, having a decayrate. For example, a voltage value of the RC circuit can have anexponential decay that decreases from the voltage of the commoncollector when the DPST switch 1212 is in an open position to a lowerthreshold voltage within a decay period, e.g., within 1-2 seconds, whenthe DPST switch 1212 is in the closed position. The decay periodrepresents a period within which BT radio 350 can receive a uniqueidentifier and/or beacon data packets from BT IC 1214. Moreparticularly, the active state of BT tag 206 may last for the decayperiod, while the timer/control circuit by design reserves sufficientenergy to control the switch to move back to the open position to put BTtag 206 into the dormant state and allow the voltage regulator 1112 andpower management IC to resume harvesting RF energy and charging storagecapacitor 1204. The lower threshold voltage can correspond to theminimum energy required to de-assert the control line to DPST switch1212. And thus, the active state can occur between the time when theenable signal to BT IC 1214 is asserted until the time when the controlsignal to DPST switch 1212 is de-asserted. By contrast, the dormantstate can occur during the time between when the control signal to DPSTswitch 1212 is de-asserted until the time when the enable signal to BTIC 1214 is asserted.

During the active state, BT radio 350 can receive the BT tag data, e.g.,operation 608. The received information can then be used by the one ormore processors of the device-case system, e.g., operation 610. The BTbeacon data packet transmission stops after all data packets have beentransmitted. After transmitting the first set of BT beacon data packetsto BT radio 350, BT IC 1214 continues to transmit beacon data packetsuntil timer/control circuit 1206 de-asserts the control line to DPSTswitch 1212. Similarly, the BT beacon data packet transmission may endin response to the switch being reset to the open position when thetimer/control circuit voltage drops to the voltage low threshold. Ineither case, if the BT beacon data packet transmission was unsuccessful,device 302 will be required to wait until the count-down timer expiresagain and another set of BT beacon data packets are transmitted toobtain the relevant data from BT IC 1214.

In an aspect, the power management IC 1202 and timer-control circuit1206 can both be reset through a mutual reset sequence each time BT tag206 transitions from the active state to the dormant state. When thetimer-control circuit observes the RC circuit voltage has dropped belowthe VLT, the timer-control circuit 1206 can issue a reset signal to thepower management IC 1202. As a result, the power management IC 1202 canbe reset to a default power-on state. As described above, the initialdefault state of the power management IC 1202 on power up requires thatthe timer-control circuit 1206 be held in reset until the powermanagement IC confirms the voltage level on the storage capacitor 1208is stable and exceeds the V_(min) (minimum operational voltage). Assuch, each time BT tag 206 transitions from the active state to thedormant state the power management IC 1202 and the timer-control circuit1206 are both reset to their default power-on states through a mutualreset sequence.

When the RC circuit voltage reaches the predetermined voltage lowthreshold value, the timer/control circuit can de-asserted the controlline of DPST switch 1212 to disconnect the power management IC 1202 fromthe BT IC 1214 to thus allow the voltage regulator 1112 and powermanagement IC 1202 to resume harvesting RF energy to recharge storagecapacitor 1204. BT tag 206 can then be in the dormant state. In thedormant state, the BT IC 1214 is prevented from continuouslytransmitting BT beacon data packets that would negatively affect BTbandwidth on device 302 needed for other BT applications. Additionally,preventing frequent BT beacon data packets also increases the availablebandwidth of device processor 306 by removing the need to process acontinuous stream of BT beacon data packets for PCV test application314. Furthermore, in the dormant state, without the load of the BT IC1214, the voltage regulator 1112 and power management IC 1202 becomemore efficient at harvesting and storing RF energy thus improving thechance the power management IC 1202 will be displaying a voltage statustrue signal to the timer-control circuit 1206 the next time thecount-down timer expires and the timer-control circuit attempts toactivate BT IC 1214 to transmit BT beacon data packets to BT radio 350.

In the foregoing specification, the invention has been described withreference to specific exemplary aspects thereof. It will be evident thatvarious modifications may be made thereto without departing from thebroader spirit and scope of the invention as set forth in the followingclaims. The specification and drawings are, accordingly, to be regardedin an illustrative sense rather than a restrictive sense.

What is claimed is:
 1. A device, comprising: an electromechanicaltransducer configured to generate an input force; one or more sensorsconfigured to generate a test output signal in response to the inputforce; and one or more processors configured to drive theelectromechanical transducer with an input signal to generate the inputforce, receive the test output signal from the one or more sensors, anddetermine whether a protective case is mounted on the device based onthe test output signal.
 2. The device of claim 1, wherein theelectromechanical transducer is a vibration motor configured to generatea predetermined vibration signal, and wherein the one or more sensorsinclude an accelerometer configured to generate the test output signalin response to the predetermined vibration signal.
 3. The device ofclaim 1, wherein the one or more sensors are configured to generate amotion signal corresponding to movement of the device, and wherein theone or more processors are configured to determine whether the testoutput signal is a valid test signal based on whether the motion signalindicates movement of the device when the test output signal isgenerated.
 4. The device of claim 1, wherein the one or more processorsare configured to determine whether the protective case is mounted onthe device based on whether the test output signal matches apredetermined impulse response signal.
 5. The device of claim 4, whereinthe one or more processors are configured to drive the electromechanicaltransducer with a baseline input signal to generate a baseline forcewhen the protective case is not mounted on the device, receive abaseline output signal generated by the one or more sensors in responseto the baseline force, and determine the predetermined impulse responsesignal based on the baseline output signal.
 6. The device of claim 4,wherein the predetermined impulse response signal is an impulse responseof a device-case system to the input force, and wherein the device-casesystem includes a reference case mounted on a reference device.
 7. Thedevice of claim 1 further comprising: the protective case mounted on thedevice, wherein the protective case includes a digital identification(ID) tag storing an identifier; and a radio-frequency transceiverconfigured to read the identifier from the digital ID tag; wherein theone or more processors are configured to determine whether theidentifier matches a reference case identifier.
 8. The device of claim7, wherein the digital ID tag is embedded in a wall of the protectivecase.
 9. A method, comprising: driving, by one or more processors of adevice, an electromechanical transducer of the device with an inputsignal to generate an input force; generating, by one or more sensors ofthe device, a test output signal in response to the input force; anddetermining, by the one or more processors, whether a protective case ismounted on the device based on the test output signal.
 10. The method ofclaim 9 further comprising: generating, by the one or more sensors, amotion signal corresponding to movement of the device; and determining,by the one or more processors, whether the test output signal is a validtest signal based on whether the motion signal indicates movement of thedevice when the test output signal is generated.
 11. The method of claim9, wherein determining whether the protective case is mounted on thedevice includes determining whether the test output signal matches apredetermined impulse response signal.
 12. The method of claim 11further comprising: driving, by the one or more processors, theelectromechanical transducer with a baseline input signal to generate abaseline force when the protective case is not mounted on the device;generating, by the one or more sensors, a baseline output signal inresponse to the baseline force; and determining, by the one or moreprocessors, the predetermined impulse response signal based on thebaseline output signal.
 13. The method of claim 11, wherein thepredetermined impulse response signal is an impulse response of adevice-case system to the input force, and wherein the device-casesystem includes a reference case mounted on a reference device.
 14. Themethod of claim 9 further comprising: reading, by a radio-frequencytransceiver of the device, an identifier stored on a digitalidentification (ID) tag of the protective case; and determining, by theone or more processors, whether the identifier matches a referenceidentifier.
 15. The method of claim 9 further comprising: transmitting,by communication circuitry of the device, verification information to aremote server, wherein the verification information includes one or moreof a level of verification that the protective case is mounted on thedevice or a percentage of time that the protective case is mounted onthe device.
 16. A non-transitory machine readable medium storinginstructions executable by one or more processors of a device to causethe device to perform a method comprising: driving, by one or moreprocessors of a device, an electromechanical transducer of the devicewith an input signal to generate an input force; generating, by one ormore sensors of the device, a test output signal in response to theinput force; and determining, by the one or more processors, whether aprotective case is mounted on the device based on the test outputsignal.
 17. The non-transitory machine readable medium of claim 16,wherein determining whether the protective case is mounted on the deviceincludes determining whether the test output signal matches apredetermined impulse response signal.
 18. The non-transitory machinereadable medium of claim 17 further comprising: driving, by the one ormore processors, the electromechanical transducer with a baseline inputsignal to generate a baseline force when the protective case is notmounted on the device; generating, by the one or more sensors, abaseline output signal in response to the baseline force; anddetermining, by the one or more processors, the predetermined impulseresponse signal based on the baseline output signal.
 19. Thenon-transitory machine readable medium of claim 17, wherein thepredetermined impulse response signal is an impulse response of adevice-case system to the input force, and wherein the device-casesystem includes a reference case mounted on a reference device.
 20. Thenon-transitory machine readable medium of claim 16 further comprising:reading, by a radio-frequency transceiver of the device, an identifierstored on a digital identification (ID) tag of the protective case; anddetermining, by the one or more processors, whether the identifiermatches a reference identifier.